Gases used in industrial processes, such as the manufacture of integrated circuits on silicon substrates, must be maintained at a high level of purity to ensure that they remain chemically active and furthermore do not contaminate the workpiece upon which they are used. The gases are often highly reactive and hazardous, and even minute amounts of moisture, oxygen or particles can have a significant adverse effect and are to be avoided.
The gases are stored in a compressed state in tanks, which have various valves, seals and fittings necessary to connect the tanks to other equipment that use the gases in the manufacturing processes. While the valves, seals and fittings are designed and manufactured to maintain the high degree of gas purity required, a challenge arises when coupling and uncoupling the fittings because there is the potential to introduce the aforementioned contaminants into the gases. This problem is effectively avoided by allowing a purge gas to flow from a fitting while it is disconnected, the purge gas effectively preventing moisture, oxygen or particles from entering the fitting and posing a contamination problem until the fitting is reconnected fluid-tight to another component.
The purge gas flow occurs at pressures between about 10 psi and 20 psi above atmospheric pressure. This relatively high pressure makes it difficult to manually install a seal in a fitting prior to attachment to a mating fitting. When the seal is seated manually it is difficult to keep the opening in the seal clear, as a finger or a thumb must apply force to the seal to properly seat it within the fitting. With the seal opening obstructed during seating, purge gas pressure builds up behind the seal, which often pops out of the fitting as a result of the purge gas pressure when the installing force is removed.
To further complicate the seal installation process, technicians often must wear bulky protective clothing due to the hazardous nature of the gases. The clothing includes gloves that prevent contamination of the seal and other hardware but also reduce tactile sensation and thus make it difficult to deftly handle the seals. Additionally, the fittings are often recessed within housings and are not visible when a seal is being installed. These complications result in lost seals, as seals are dropped during installation or ejected from the fitting due to purge gas pressure build-up, and cause significant lost time and added expense to the industrial process in which the gas is used. There is clearly a need for a tool and a method to facilitate installation of seals in fittings through which purge gas is flowing.